I discussed this exact issue with my FS when we began stimming for a second baby. We decided that we were committed to using every embryo created, however we didn't want more than 3 children- preferably 2.

So our FS suggested that they only fertilise six eggs. He said that if the statistical 80% fertilise then we should get 4-5 embryos and if, best case scenario 50% cause a pregnancy then we would have 2 babies.

He then said more times than not the statistics for my particular case would be an absolutely best possible outcome. I ended up with one baby and one miscarriage - so pretty spot on.

I would discuss your concerns with your FS and maybe consider not fertilising heaps of eggs.

Good luck